Cylinder air port construction



Jufiy W, NEW c. F. PERVHER CYLINDER AIR PORT CONSTRUCTION Filed Oct. 2, 1947 INVENTOR.

ATTORNEY Patented July 17, 1951 UNITED STATES PATENT OFFICE CYLINDER AIR PORT CONSTRUCTION Charles Frank Pervier, Port Washington, Wis., assignor to Harnischfeger Corporation, Milwaukee, Wis., a corporation of Wisconsin Application October 2, 1947, Serial No. 777,539

2 Claims. 1

The invention relates to internal combustion engines and more particularly to the cylinder construction of two cycle engines.

In the usual cylinder constructions for two cycle uniflow engines the liner is provided with a belt of air inlet ports uncovered by the piston as it nears the end of its outward or power stroke. Heretofore, in the manufacture of these cylinders after the liner has been finished honed or ground to a uniform bore diameter, it has been necessary to relieve or provide a small clearance in the liner in the region containing the air inlet ports as it has been found that if this is not done after the engine becomes heated up in running that the liner at the inlet port region causes piston seizure. The object of the present invention is to provide a liner or cylinder in which the inlet ports and the walls of the liner surrounding the same are so constructed and arranged that the ported portion of said liner provides an expandible cooled wall which will vary in diameter in conformity with the rest of the liner, thereby eliminating the usual costly and time-consuming step of relieving the bore of the liner at the inlet ported portion thereof.

The invention further consists in the several features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

Referring to the drawings:

Fig. 1 is a vertical sectional view through an engine cylinder embodying the invention, the section being taken along the broken line l| of Fig. 2;

Fig. 2 is a detailed horizontal sectional view taken on the line 22 of Fig. 1;

Fig. 3 is a side elevation view of the ported portion of the cylinder liner, parts being broken away;

Fig. 4 is a detailed vertical sectional view through the liner taken on the line 4-4 of Fig. 3.

Referring to the drawings, the numeral 5 designates generally the cylinder supporting frame of the engine having side walls 6 and 1 integrally connected with a head seat portion or entablature 8. The head seat 8 is vertically bored to receive the cylinder head portions of the removable cylinders embodying the invention.

The side walls 6 and 1 connect with an integral crankcase portion 9 of the frame 5, and at this point the frame is provided with a horizontal chambered partition 10 which is provided with bores aligning with the bores in the head seats so as to receive the lower ends of cylinder barrels of the cylinder assemblies inserted through 'said head seat openings. The partition l0 separates the crank chamber II from an'air box chamber [2 formed by the side walls 6 and 1, and it is also chambered to provide coolant chambers I3 adjacent the lower ends of the inserted cylinder barrels and communicating with a header (not shown) for conducting coolant thereto.

Inserted within the bores in the entablature 8 and extending downwardly through the bores in the partition H] are cylinders or cylinder assemblies made up of a head portion l4 threadingly attached to the upper end of a tubular cylinder barrel !5 in which the engine piston (not shown) works.

Each barrel I5 is formed to provide a cylinder of substantially uniform cross sectional area throughout its length except in the region of the air inlet ports I6 where its area is increased to provide the necessary stock for forming the ports l6 and the vertically bored passages ll between the ports for connecting the upper and lower cooling jacket spaces l8 and IS.

The upper cooling space I8 is formed by the barrel, head and a sheet metal tube 20 secured at its lower end 2| to the ported portion of the barrel, as by brazing, and at its upper beaded end over and in compressible engagement with a resilient O-ring gasket 23 of rubber or other suitable material which is seated in an annular groove 24 formed in the lower part of the head portion M.

The lower cooling space I9 is formed by the barrel, a sheet metal tube 25, and a coolant port ring or gland 26 having gasket engaging shoulders or seats Zl and 28. The tube 25 is secured at its upper end to the lower edge of the ported portion of the barrel, as by brazing and similarly secured at its lower end to the ring 26. The seats 21 and 28, respectively, engaging compressible sealing gaskets 29 and 30 interposed between said seats and seats formed in the inner walls of the bores formed in the partition I, seal the upper and lower parts of the chamber I3.

That portion of the ring 26 extending through the chamber I3 is provided with radially disposed ports 3| which communicate at their inner ends with vertically disposed ports 32 have flared upper ends, said ports establishing communication between the chamber l2 and the space [9.

The head portion I4 is jacketed to provide a cooling space 33 connected at its lower end with the upper end of the space l8 by a series of peripherally spaced upwardly inclined passages 34 and connected at its upper end by one or more passages 35 with a passage or passages 36' connecting with a coolant space 36 formed in the side frame 4 and surrounding the exhaust conduits 31 of the engine.

Thus coolant supplied to the header flows therefrom to the chambers l3 for each of the cylinders and through ports 3| and 32 to the cooling spaces 19 of said cylinders and then through the passages I1 to the spaces [8, thence through the passages 34 to the head jacket 33 and from this jacket by way of passages 35 and 36 to spaces 36, the header l and space 36 being connected to the usual cooling radiator and a pump for continuously circulating. the coolant.

The cylinder assembly comprising the head l4, barrel I5, and jacketing membersabove described form a unitary assembly adapted to ."removably fit in the bores of the parts 8 and ll) of the engine frame. When inserted in the frame-each cylinder is held in place by a plurality of hold down bolts 38 passing through the head portion l4of the cylinder and anchored in the entablature 8 -of-the frame.

iTheparticular feature intended to be covered by the present application isthe form .of the 'thickened belt portion 39 of the barrel-and-the :form and arrangement of the inlet ports I6 in said belt portion.

According to the present invention, the thick- ;ened belt portion 39 of the barrel hasthe inlet .ports l6 formed therein by a series of rectangular slots 49 extending'transversely of said belt'39 and preferably tangentially inclined relative to the'axis of the barrel to impart a swirl to the air introduced into the cylinder, said slots pref- 'erably being'formed by a circular milling cutter,

sothat the tops and'bottoms of saidslots are ciry.

r-cularly or cylindrically curvedand flare out- -wardly-from their-inner ends 4| totheir outer ends '42, .the edges 43 of-the ports preferably ,beingsmoothed off after the milling operation.

The top and bottom edges of the portion .39 .are

also preferably provided with annular grooves 44 that may have curved bottoms as shown wherebymetal is removed from the .thickened portion .of the belt and so that the outer ends of the slots extend substantially to the end edges of. said .thickened portion.- .The grooves l lalso facilitate the-drilling of the transfer holes I! andalso re- ,duce the cross-sectional areas of the parts of said belt where the tubes and.25 are secured thereto by brazing to aid in the brazing operation. The ported area of the belt portion 39-is at least as great as the'bridge portions '45 between -said'ports and each ofsaid bridge portions has the coolant transfer passageor hole I! therein :forefiicient cooling of thebelted portion of the cylinder.

Owing to the flaring of the port, considerably more metal is removed from the thickened. por- ,.tion of the barrel l5 than where the ports areof uniform cross-section throughout their. length .and further owing to the factthat the slots are cylindrically flared still more metaljis removed than where the portshave straight inclined end surfaces. Thus the long cylindrically curved slots 40 break up the circumferential continuity of the thickened portion of the barrel, so that after the barrel is finished honed, the ported portion which is always cooler can more easily follow the dimensional changes of the adjacent warmer portions of the barrel during therunning of the engine. The hollow bridges 45 0f the thickened portion'39 provide the necessary longitudinal rigidity to compel the cylinder surfaces in the vicinity of the ports I6 to follow the dimensional changes of the adjacent cylindrical surfaces with the result that a cylinder wall whose diameter under temperature changes will vary comparatively uniformly throughout its length is provided, thereby eliminating the usual costly and time-consuming stepof relieving the bore --at its ported portion.

I desire it to be understood that this invention "is not to be limited to any particular form or arrangement of parts except in so far as such limitations are included in the claims.

What I claim as my invention is:

v1. In :a -cylinder for internal combustion en- "ginesga cylinder 'barrel having a belt portion of greater thickness than the remainder of the barrel, air inlet ports circumferentially arranged about the periphery of said belt portion formed of elongated slots transversely arranged with respect ,to..said .beltwith the longer dimension of .said slots extending axially with respectto-said ,slots being of such curvature and extent asLto substantially subtend the axialextent of said belt, bridge portions betweensaid slots, the spacing of said slots and bridge portions being .such that the-,portedareaof said belt portion is .at.least .equal to the area of saidbridge portions, wherebythecircumferential continuity of said beltpor- .tion is interrupted to an extent suflicient to cause the same substantially to follow dimensioned .changes in the diameter of the remainder ofsaid barrel.

2. In a cylinder for internal combustion .en- .gines, .a .cylinder barrel having a belt portion of greater thickness than the remainder of the barrel provided with a series of circumferentially spaced inlet ports having flared inlet ends and bridge portions between said ports with coolant passages extending therethrough, the top and bottom portions of said belt,portion having .annular grooves disposed parallel to the bore of said barrel and reducing the thickness of the same, the area. of said portedportions andsaid grooves being atleast equal to the area of .said

bridge portions and said ports extending substantially transversely of said belt portion with their-outer ends extending substantially to the top and bottom portions of said belt portion to .provide a ported portion free to expand and contract .in substantial uniformity with the remainder of the barrel.

CHARLES FRANK PERVIER.

I REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,664,782 Magdeburger Apr. '3, .1928 1,751,653 Nibbs Mar. 25, 1930 1,968,110 Walker July 30,.193e 2,018,848 Gruebler Oct. 29, 1935 2,371,297 Huber Mar. 13, 19.45 

